Merged Pull Requests Have Stopped Appearing in JIRA Commits Tab

Merged pull requests on or before Jan 2 2014 appear properly in JIRA issues on the Commits tab (because we use a standard naming strategy of including the JIRA ID in the branch, like this: "ABC-123.My-New-Feature").

But more recent merged pull requests are not appearing in JIRA, even though when I view the commits list on Bitucket I can click the hyperlink'd JIRA ID in the (grayed out) pull request merge commit and navigate to the JIRA issue.